(a) Field of the Invention
The present invention relates to an apparatus for detecting location information of a target, and more particularly, to an apparatus for detecting location information of a target by which the number of transmitting or receiving antennas needed for detecting an angle of the target is reduced.
(b) Description of the Related Art
A radar, which is an acronym for radio detecting and ranging, is a wireless detection device that transmits an electromagnetic wave such as a microwave to a target, receives the electromagnetic wave reflected from the target, and determines a distance from, a direction of, an altitude of the target.
The radar uses a microwave of a wavelength of 10 cm to 100 cm that has a straight traveling property such as light since it has a short wavelength. Since the microwave is not reflected from an ionosphere, a radio wave emitted from a directional antenna travels straight to the target and is then reflected back to the antenna. Subsequently, a time for which the electromagnetic wave is reflected back may be measured to obtain information about a distance from, an angle with respect to, a speed of the target, and a terrain, formation of clouds, a location of an aircraft, etc. can be identified using the obtained information.
A tracking radar constantly measures coordinates of the target to identify movement of the target, and provides data for estimating the target's path and future location. In addition, a detecting radar has a low precision compared to the tracking radar, but has a long detecting range and allows an early detection of a distant target.
Generally, radars use a plurality of transmitting antennas and a plurality of receiving antennas to set a wide field of view (FOV).
FIGS. 1A to 1C are drawings that illustrate antenna structures of a radar according to the conventional art.
First, FIG. 1A is a drawing that illustrates a method for using one transmitting antenna and a plurality of receiving antennas. If multiple targets are present within the same FOV when one transmitting antenna is used and, an error may occur during a process of identifying the targets. In addition, a large number of receiving antennas is required to improve detecting performance.
On the contrary, FIG. 1B is a drawing that illustrates a method for using a plurality of transmitting antennas and a plurality of receiving antennas. As shown in FIG. 1B, the respective transmitting antennas are set to have different FOVs and are selected by a switch after each time interval, and the selected antenna transmits the signal that is selected for the corresponding time slot. This method requires the plurality of transmitting antennas, and a very precise work of installation of the respective transmitting antennas is required for correct detection.
In addition, FIG. 1C is a drawing that illustrates an antenna structure of a radar using a digital beam-generating technique. This technique allows the transmitting antenna to transmits signals for electrical scanning, and is more flexible than the method illustrated in FIG. 1B. However, even this technique requires a plurality of transmitting antennas and a plurality of receiving antennas to improve detecting performance.
When a low frequency radar or an ultrasonic wave is used, the antenna increases a size of an entire radar system. The background technology of the present invention is disclosed in Korean Patent Application No. 10-1221570 (Jan. 14, 2013).